Which term describes the plaque biofilm on teeth that can come to be dominated by cariogenic bacteria under acidic conditions?

• A. Enamel
• B. Plaque
• C. Calculus
• D. Gingival fluid

Answer: (B)

Dental plaque is the biofilm that forms on tooth surfaces. It’s a dynamic microbial community embedded in a sticky matrix, and it can shift in composition when conditions change. When fermentable sugars are present, the bacteria in plaque produce acid, lowering the local pH. In this acidic environment, cariogenic bacteria such as Streptococcus mutans and lactobacilli thrive and become the dominant members of the biofilm. This dominant, acid-producing community within the plaque is what drives caries risk at the tooth surface. Enamel refers to the tooth surface itself, calculus is mineralized plaque, and gingival fluid is the liquid from the gum crevice, not the biofilm on the tooth.